Nano-ridge engineering of GaSb for the integration of InAs/GaSb heterostructures on 300 mm (001) Si

Nano-ridge engineering (NRE) is a novel heteroepitaxial approach for the monolithic integration of lattice-mismatched III-V devices on Si substrates. It has been successfully applied to GaAs for the realization of nano-ridge (NR) laser diodes and heterojunction bipolar transistors on 300 mm Si wafers. In this report we extend NRE to GaSb for the integration of narrow bandgap heterostructures on Si. GaSb is deposited by selective area growth in narrow oxide trenches fabricated on 300 mm Si substrates to reduce the defect density by aspect ratio trapping. The GaSb growth is continued and the NR shape on top of the oxide pattern is manipulated via NRE to achieve a broad (001) NR surface. The impact of different seed layers (GaAs and InAs) on the threading dislocation and planar defect densities in the GaSb NRs is investigated as a function of trench width by using transmission electron microscopy (TEM) as well as electron channeling contrast imaging (ECCI), which provides significantly better defect statistics in comparison to TEM only. An InAs/GaSb multi-layer heterostructure is added on top of an optimized NR structure. The high crystal quality and low defect density emphasize the potential of this monolithic integration approach for infrared optoelectronic devices on 300 mm Si substrates

Correlation between surface reconstruction and polytypism in InAs nanowire selective area epitaxy

Themechanism of widely observed intermixing of wurtzite and zinc-blende crystal structures in InAs nanowire (NW) grown by selective area epitaxy (SAE) is studied. We demonstrate that the crystal structure in InAs NW grown by SAE can be controlled using basic growth parameters, and wurtzitelike InAs NWs are achieved.We link the polytypic InAs NWs SAE to the reconstruction of the growth front (111)B surface. Surface reconstruction study of InAs (111) substrate and the following homoepitaxy experiment suggest that (111) planar defect nucleation is related to the (1 × 1) reconstruction of InAs (111)B surface. In order to reveal it more clearly, a model is presented to correlate growth temperature and arsenic partial pressure with InAs NW crystal structure. This model considers the transition between (1 × 1) and (2 × 2) surface reconstructions in the frame of adatom atoms adsorption/desorption, and the polytypism is thus linked to reconstruction quantitatively. The experimental data fit well with the model, which highly suggests that surface reconstruction plays an important role in the polytypism phenomenon in InAs NWs SAE.https://doi.org/10.1103/PhysRevMaterials.1.074603Peer Reviewe

Observation of the stacking faults in In0.53Ga0.47As by electron channeling contrast imaging

The observation and interpretation of Frank stacking faults, Shockley stacking faults, Lomer dislocations, and 60 degrees misfit dislocations, which have similar line shapes in the (001) In0.53Ga0.47As crystalline surface, are performed with the electron channeling contrast imaging (ECCI) technique. To minimize the backscattered electron (BSE) contrast that resulted from the surface morphology, a relatively flat region is first selected and compared with an atomic force microscopy (AFM) image and then, subsequently, examining ECCI with transmission electron microscopy (TEM)-like invisibility criteria. By orthogonally choosing the diffraction vector g between (220) and (2-20), misfit dislocations seem to be always visible but partially faint in the g parallel to the line direction on the surface. With respect to the image contrast, Frank stacking faults and Lomer dislocations are likely to be completely invisible for parallel g. The criteria are further confirmed by cross-sectional TEM analysis, which shows a preferred homogeneous surface nucleation

EuReCa ONE—27 Nations, ONE Europe, ONE Registry A prospective one month analysis of out-of-hospital cardiac arrest outcomes in 27 countries in Europe

AbstractIntroductionThe aim of the EuReCa ONE study was to determine the incidence, process, and outcome for out of hospital cardiac arrest (OHCA) throughout Europe.MethodsThis was an international, prospective, multi-centre one-month study. Patients who suffered an OHCA during October 2014 who were attended and/or treated by an Emergency Medical Service (EMS) were eligible for inclusion in the study. Data were extracted from national, regional or local registries.ResultsData on 10,682 confirmed OHCAs from 248 regions in 27 countries, covering an estimated population of 174 million. In 7146 (66%) cases, CPR was started by a bystander or by the EMS. The incidence of CPR attempts ranged from 19.0 to 104.0 per 100,000 population per year. 1735 had ROSC on arrival at hospital (25.2%), Overall, 662/6414 (10.3%) in all cases with CPR attempted survived for at least 30 days or to hospital discharge.ConclusionThe results of EuReCa ONE highlight that OHCA is still a major public health problem accounting for a substantial number of deaths in Europe.EuReCa ONE very clearly demonstrates marked differences in the processes for data collection and reported outcomes following OHCA all over Europe. Using these data and analyses, different countries, regions, systems, and concepts can benchmark themselves and may learn from each other to further improve survival following one of our major health care events

Metamorphic InGaP/InGaAs Multijunction Solar Cells on Germanium Substrates (Metamorfe InGaP/InGaAs multi-junctie zonnecellen op germanium substraten)

Roosteraangepaste en metamorfe III-V multi-junctie zonnecelontwikkeling wordt in deze thesis beschreven. Meer specifiek die van In0.495Ga0.505P / In0.01Ga0.99As en In0.65Ga0.35P / In0.17Ga0.83As twee-junctie cellen op germanium. In combinatie met een germanium bodemcel kunnen ze gebruikt worden als bovenste deel in de mechanische stapeling die op imec onder ontwikkeling is. Deze structuur kan toegepast worden voor elektriciteitsproductie in de ruimte (bv. voor satellieten) of in aardse concentratiesystemen. Theoretische berekeningen geven een bovengrens voor de efficiëntie van de roosteraangepaste cel, nl. 32.5 en 36 % onder respectievelijk AM0 en 500×AM1.5D belichting. Voor de metamorfe cel is dat respectievelijk 34.2 en 41.8 %. Eerst wordt in twee theoretische hoofdstukken de depositietechniek (MOVPE) en de bronmateriaalkeuze verduidelijkt en de werking van de zonnecel en de tunneljunctie behandeld. Vervolgens wordt de ontwikkeling van de roosteraangepaste 2-junctie cel gepresenteerd. De beste 1-junctie In0.01Ga0.99As en In0.495Ga0.505P cellen hadden een conversie-efficiëntie van 24.7 en 14.2 %. Een AlGaAs tunneljunctie met een piekstroomdichtheid van 92 A/cm2 werd gerealiseerd. Met deze componenten werd een 24.3 % efficiënte tandemcel gemaakt. Ten slotte wordt een 18.6 % efficiënte metamorfe 2-junctie cel gemaakt vertrekkend van een 17.0 % efficiënte In0.17Ga0.83As en een15.2 % efficiënte In0.65Ga0.35P 1-junctie zonnecel en gebruik makende van een AlGaAs tunneljunctie met een piekstroomdichtheid van 13.5 A/cm2. Hiervoor werd een geschikte bufferlaag ontworpen om de roostermisaanpassing op te vangen en te vermijden dat dislocaties doordringen in de actieve lagen van de component.CHAPTER 1 INTRODUCTION 1 1.1 Towards renewable energy production 1 1.2 Solar power 4 1.3 High-efficiency III-V solar cells 7 1.4 The dual junction III-V solar cell 11 1.5 Thesis outline 13 1.6 References 14 CHAPTER 2 METALORGANIC VAPOUR PHASE EPITAXY 17 2.1 Introduction 17 2.2 Principle of operation 18 2.3 Thermodynamics 20 2.4 Metalorganic group-V precursors 23 2.5 Reaction kinetics 26 2.6 The boundary layer 29 2.7 Conclusion 31 2.8 References 32 CHAPTER 3 THEORY OF SOLAR CELL AND TUNNEL JUNCTION 33 3.1 Introduction 33 3.2 Solar cells 34 3.3 The tunnel junction 42 3.4 Conclusions 49 3.5 References 50 CHAPTER 4 LATTICE-MATCHED MATERIALS 51 4.1 Introduction 51 4.2 Growth on germanium 52 4.3 In0.01Ga0.99As single junction solar cell 53 4.4 In0.495Ga0.505P single junction solar cell 61 4.5 Carbon doping and tunnel junctions 88 4.6 The InGaP/GaAs dual junction solar cell on Ge 107 4.7 Summary and conclusions 111 4.8 References 113 CHAPTER 5 METAMORPHIC MATERIALS 117 5.1 Introduction 117 5.2 Buffer layers 118 5.3 In0.17Ga0.83As single junction solar cell 127 5.4 In0.65Ga0.35P single junction solar cell 142 5.5 AlGaAs tunnel junction 146 5.6 In0.65Ga0.35P/In0.17Ga0.83As tandem solar cell 154 5.7 Summary and conclusions 159 5.8 References 160 CHAPTER 6 SUMMARY AND OUTLOOK 163 6.1 Introduction 163 6.2 Results 164 6.3 Outlook 166 6.4 References 171status: publishe

Plant peptones: Nutritional properties sustaining recombinant protein secretion by CHO cells

The network metabolic model of High-FiveTM insect cells based on the consumption / production of metabolites and the protein, DNA/RNA, lipid and carbohydrates content of the cells has made it possible to study the internal fluxes of these cells’ metabolism

Origin of rice protein hydrolysates added to protein-free media alters secretion and extracellular proteolysis of recombinant interferon-gamma as well as CHO-320 cell growth

CHO-320 cells, cultivated in suspension in a protein-free medium supplemented with rice protein hydrolysates (peptones), secrete recombinant interferon-gamma (IFN-gamma) that undergo will or will not proteolysis, depending on the origin of the peptones. This proteolytic event, as well as the appearance of an unidentified 70 kDa gelatinase-like protease, are attributed to a cysteine protease. Casein zymographies revealed that one rice protein hydrolysate, but not another, contains a papain-like cysteine protease whose activity is undetectable in solution. This work underlines the significance of the origin of peptones when considered as supplements in serum- and protein-free media for overproduction of recombinant proteins

Aetiologies of Fever after a Stay in the Tropics: A One Year Prospective Study in the Emergency Department of the Saint Pierre University Hospital, Brussels Belgium

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